Variable pitch propeller



May 16, 1933.

J. EDMAN VARIABLE PITCH PROPELLER Filed Nov. 4, 1951 5 Sheets-Sheet l Ill-I' l -'Illllllllllllllllllllllllillll 1/41/1 5 Y 4/ /4 9 Y B Jbbzw $0 1190];

May 1 6, 1933. EDMAN 1,908,893

VARIABLE PITCH PROPELLER Filed Nov. 4, 1951 s Sheets-Shefi 2 May 16, 1933. 4 J. EDMAN 1,908,893

VARIABLE PITCH PROPELLER Filed Nov. 4, 1931 3 Sheets-Sheet 3 jZig. 4

Patented May 16, 1933 UNITED STATES PATENT OFFICE JOHN EDMAN, OF MINNEAPOLIS, MINNESOTA, ASSIGNOR .OF ONE-HALF TO GUNNAB F. SEASHORE, OF MINNEAPOLIS, MINNESOTA VARIABLE PITCH PROIE'ELLER Application filed November 4, 1931. Serial No. 572,954.

My invention provides an improvement in variable pitch propellers and, generally stated, consists of the novel devices, combinations of devices and arrangement of parts hereinafter described and defined in the claims. While adapted for more general use, the improved propeller has been especially designed for use in connection with aeroplanes and other aircraft.

It is a well known fact that aeroplane propelle'rs, for example, operate very differently in atmospheres of different density and that propellers set for proper action in the lower atmospheres will, at high altitudes or as the plane approaches the stratosphere permit the engines to race due to the low resistance of the rarified air. Hence, variable propellers are required in allaeroplanes that are designed to reach very high altitudes or to approach the stratosphere. Of course, there are many other reasons for the use of vari- Y able pitch propellers. For instance, in taking an aeroplane'olf from the ground, the

5 best results can be obtained by setting the propeller blades at a relatively small angle to the plane of rotation of the propeller. For obtaining high speed, the propeller blades should be set at increased angle to the plane 'of rotation of the propeller. Generally stated, by the use of variable pitch propeller blades, the motor can be kept rotating at its most effective speed and various atmospheric conditions can be met. Also, by reversing the pitch of the propellers, they may be used as a brake to slow up the speed of an aeroplane in landing. I

In the accompanying drawings, the invention is illustrated as applied to an aeroplane and referring to these drawings, wherein like characters indicate like parts throughout the several views Fig. 1 is a fragmentary view partly in sec- V tion and partly in diagram and with some parts broken away showing the front end portion of an aeroplane and showing the improved propeller applied thereto;

Fig. 2 is a fragmentary View partly in plan and partly in section on the line 22 of Fig. 1, some parts being in diagram;

Fig. 3 is a horizontal section taken approximately on the line 33 of Fig. 2;

Fig. 4 is an enlarged vertical section taken on the line 44 of Fig. 3, some parts being broken away and some parts being shown in full;

Fig. 5 is a detail in section on the line 55 of Fig. 4;

Fig. 6 is a plan view of the parts found just under the line marked 66 on Fig. 3, but showing also the upwardly projected blade in full;

Fig. 7 is a detail looking at the face of the instrument board and showing the parts applied thereto;

Fig. 8 is a section taken on the line 88 of Fig. 2; and

I Fig. 9 is a fragmentary View corresponding in the line of'its section to Fig. 4, but illustrating a somewhat modified form of blade mounting.

Of the parts of the aeroplane shown, the fuselage is indicated as an entirety by the numeral 10, the windshield by the numeral 11, the instrument board by the numeral 12, the engine block by the numeral 13, and the engine crank shaft by the numeral 14.

The engine crank shaft 14 at its front end projects through the front end of the fuselage and at its front end considerably in advance of the fuselage; it is provided with a rigidly secured propeller hub shown to said inner hub section 15. The propeller blades 17 are rigidly secured to spindles 18 by suitable means such as rivets or bolts 19. The spindles 18 are mounted in the hub 1516 in diametrically opposite radial arrangement and at their inner ends are provided with pinions 20 located in suitable recesses formed therefor in inner hub member 15. In the preferred arrangement, the mounting of the spindles in the outer hub member 16 is accomplished as follows:

The inner portions of said spindles are provided with thrust shoulders formed by an enlarged flange 21 and are mounted within split sleeves 22 that are made up of semicylindrical sections which when put together form a complete sleeve. These sleeves are mounted in suitable seats formed in the hub member 16 and are provided at their inner ends with threads 23 and at their outer ends with threads 24. The threads 23 engage internal threads of the hub member 16 while the outer threads 24 are engaged by an annular nut 25 that presses anexpansible conical wedge 26 between the split sleeve and its seat in the hub section 16. Anti-friction thrust bearings 27 are interposed between the thrust collars 26 and the outer ends of the co-operating split sleeves and the inner portions of the spindles 18 are journaled within the split sleeve by means of annular anti-friction bearings 28. The sleeve structure just described has the advantage that it can be assembled without removing the propeller blades from their spindles 18.

The connection between the spindles 18 and the pinions 20 are preferably made by annular shanks 29 on the inner ends of said spindles and onto which the said pinions are loosely telescoped. The extreme inner ends of the spindles 18 are made round, as shown at 30, and are seated in the inner hub member 15 so that they give good bearings for the propeller blade spindles. It has now been shown that the propeller blades are mounted for angular adjustments in respect to the plane of rotation of the propeller, that is, the plane at ninety degrees to the axis of rotation of the propeller shaft and in which plane the axes of the propeller blades are mounted to travel.

Means for controlling and setting the adjustments of the propeller blades as preferably arranged is as follows:

The pinions 20 are engaged by rack bars 31 that are mounted for sliding movements .in the hub 1516 and engage their respective pinions 20 on opposite sides thereof. These racks 31 at their rear ends are secured to a disc-like thrust plate 32 that is keyed to the shaft 14 for rotation therewith, but for sliding movements thereon. The rim of thrust late 32 on opposite sides, is engaged by antl-fric'tion thrust bearings 33 that are retained in an annular non-rotary shifter head, shown as made up. of two members 34 and 35 connected by threaded engagement, the latter member, as shown, being mounted 37, as best shown in Fig. 2. Working with threaded engagement on the adjusting screws 36, between the head plate 37 and 38, are nutacting gears 39. As shown, there are four of the screws 36 and hence four of the gears 39.

These gears 39 as best shown in Fig. 8, are circumferentially spaced around the axis of the shaft 14 and are in intermeshing engagement. One of the gears 39 is also in mesh with the similar outwardly located gear 40 that is secured. to the front end of a jointed shaft 41. The front end section of shaft 41 is journaled in the head plates 37 and 38 between which the gear 40 is also located. The rear end section of jointed shaft 41 is extended through and mounted in the instrument board 12 and at the rear of said board is provided with an operating handle or wheel 42 best shown in Fig. 1.

As best shown in Fig. 3, the space between the shifter head and the fuselage is closed by an annular flange 43 secured to the fuselage For indicating the ad ustments or angular positions of the propeller blades, an indicator is preferably applied to the instrument board and connected to the shaft 41. This indica-- tor may take Various forms but, as shown, comprises a pinion 45 secured to the rear end section of said shaft 41 and meshing with a larger gear 46 secured to a short shaft 47 that is journaled in and extended through the instrument board and at its front end is provided with a pointer 48 that co-operates with a graduated scale 49 to indicate the said angular adjustments of the propeller blades. In Fig. 7, the pointer 48 is at zero indicating that the blades at such time will be at zero pitch or in other words, at no angle in respect to the plane of rotation. In the drawings, the blades when shown, are in angular positions at which time the pointer 48 would be set to the right at a two or three degree of pitch.

WVhen the parts are assembled as above described, the sections of the'split sleeves 22 will, of course, be held rigidly in perfect alignment first, by the screw engagement 23 and further by the clamping action of the compressible wedge-acting cone 26; and as already indicated, it is not necessary either in assembling the parts or dis-assembling them, to remove the rivets or bolts 19 that connect the blades 17 to their spindles 18.

.It is of course, evident that by manipulation, the handle or Wheel 42 can quickly set the propeller blades at any angle desired and that the blades when set, will remain set against accidental movement, inasmuch as their movement is locked or made irreversible by the threaded engagement between the shifting screws 36 and nut-acting gears 39. Not only can the blades be set atany desired angle for forward travel, but may be reversed when retarding or brake action is required.

In the modified structure illustrated in Fig. 9, the sleeve 50 which takes place of split sleeve 22 previously described is an integral or one-piece sleeve and is provided at its inner end with a removable head 51, which permits insertion and removal of the antifriction bearings 52 and 53. In this arrangement also, in the dis-assembly of the parts, it is necessary to remove the rivets or bolts 19 that connect the blades to their spindles.

From the foregoing, it is evident that the device described is capable of various modifications as to details of construction and arrangement of parts within the scope of the invention herein disclosed and claimed.

What I claim is:

1. In combination withan engine and an engine-driven shaft, a hub mounted on said shaft, propeller blades projecting from the hub and having spindles journaled in said hub, pinions working in the hub and mounted one on each of said spindles for rotary movements therewith, a non-rotary shifter head working over said engine-driven shaft for axial shifting movements in respect thereto, an annular rotary thrust plate working in said head for shifting'movements therewith and rotary movements with the shaft, racks carried by said thrust plate and projecting therefroin' into said hub and meshingone with each of said pinions, and means for imparting axial shifting movements to said head, including adjusting screws projecting fromsaid head in circumferentially spaced relation about the engine shaft, and intermeshing nut-acting gears one oneach of said screws.

2. In combination with .an engine and an engine-driven shaft, a hub mounted on said shaft, propeller blades projecting from the hub and having spindles journaled' in said hub, pinions working in the hub and mounted one on each of said spindles for rotary movements therewith, a non-rotary shifter head working over said engine-driven shaft for axial shifting movements in respect thereto an annular rotary thrust plate working in said head for shifting movements therewith and rotary movements with the shaft, racks carried by said thrust plate and ing one with each of said pinions, means for imparting axial shifting movements-to said head including adjustment screws projecting from said head in circumferentially spaced relation about the engine shaft, intermeshing nut-acting gears one on each of said screws, and .a gear offset from said intermeshing gears but meshing with one thereof and having operating connections extending therefrom past the engine.

In testimony whereof I aflix my signature.

JOHN EDMAN'.

projecting therefrom into said hub and mesh 

